I've discovered a lot of new bands through said links on sites I frequent, purely because you're not looking at a line of impersonal/meaningless letters. It draws you in. It's human nature.

I know what you're saying, it's not just window dressing. A preview picture could spark curiosity and the imagination(for people blessed with those qualities).
Of course the content is what's important but a little lure to the content might get viewers that otherwise would pass on it and miss out.